Electrodeposition of nickel



Patented Apr. 19, 1949 I ELEGTRODEPOSITION OF NICKEL Henry Brown, Detroit, Mich, asslgnor to The Udylite Corporation, Detroit, Mich, a corporation of Delaware No Drawing. Application August 21, 1943, Serial No. 499.517

6 Claims.

This invention relates to the electrodeposition of nickel from an aqueous acid bath.

The object of this invention is the electrodeposition of a bright ductile nickel plate having good bond to the basis metal. This object can be achieved by the addition of sulfonic acid derivatives of aryl sulfones to an aqueous acid nickel bath.

These compounds are listed in Table I with their optimum concentration in baths prepared from nickel sulfate, nickel chloride and boric acid and containing about '75 g./l. Ni, 15 g./l. Cl and 35 g./l. H3303. The temperature of the plating solution can range from room temperature to boiling and preferably from room temperature to 60 C., ordinarly 55 C. The pH of the solution may vary between 1.5 and 6 and preferably between 2 and 5. The current density generally varies between .5 and 5.5 amp./ dmfi. Ordinarily about 4 amp./dm. is employed at a pH of 3.5 and a temperature of 55 C. Higher current densities may be used at higher metal content, or higher temperature, or lower pH, or with increased agitation.

The presence of other inorganic salts such as NH4 and Na salts does not interfere with the beneficial action of these organic compounds as long as inorganic materials are present in such amounts which are common in ordinary white nickel baths. Thus the invention is not limited to any specific nickel plating bath and can be used in double nickel salt baths or in straight chloride baths as well as in the standard Watts bath.

Table I Conc. g./l. 4i

Diphenyl sulfone-3-sulfonic acid 1 Dlphenyl sulfone-3,3'-disu1fonic acid 1-5 1,1'-dinaphthyl sulfone-5,5'-disul1onlc acid 1-3 2,2'-dinaphthy1 sulfone-l,'l-disulionic acid" 1-3 no swsomsoin The above are preferred examples of the sulfonic derivatives of aryl sulfones, though other examples can be used such as the sulfonated derivatives of phenyl p-tolyl sulfone, ditolyl sulfone 3-sulfonic acid, benzene 3-sulfonic acid methyl sulfone and others. The di-diphenyl sulfone sulionic acids and the alkyl substituted derivatives in general are not very soluble in the presence ofhigh concentrations of salts in the bath and though useful are not preferred examples. Preferably the sulfonated aryl sulfones should not have an -NH2 or an -N02 or an -OH group attached to the aryl ring.

The best examples are the diphenyl sulfone sulfonic acids which are the simplest to prepare at the present. The sulfonated aryl sulfones can be added in the acid form or as the nickel salt or even as the sodium salt or as the salt of any other metal except a metal which produces a harmful result in the bath, e. g., a copper salt would be detrimental in the bath.

These sulfonated aryl sulfones produce excellent grain refinement in acid nickel plating baths. I The plates obtained on bufied or brilliant subsurfaces are brilliant. Furthermore the nickel plating baths are made more tolerant to small percentages of foreign metallic ions such as Zn, Cd++, 'I'l+, Cu++, etc. and also to organic compounds that would otherwise make the nickel plate be less ductile and less adherent.

The aryl sulfone group at least on benzene nuclei is more important than the aryl sulfonic group insofar as the beneficial efiects on the nickel plate are concerned. For example, benzene sulfonic acid or meta benzene disulfonic acid or diphenyl sulfonic acid or diphenyl disulionic acid do not produce nearly as good results as does diphenyl sulfone 3-sulfonic acid or diphenyl sulfone 3,3'-disulfonic acid. That is, the plates obtained are not as bright and they will not permit use of as high concentrations of zinc or organic substances without getting plate that is very brittle and of poor appearance.

It should be noted that there is nothing critical about the concentration oi these sulfonated aryl and its modifications, using formates, cltrates, etc., as well as horic acid as buffers. The most suitable nickel plating baths and their temperatures and preferred hydrogen ion concentration are given in Table II. anall concentrations of citric acid especially, and also of formic, can oftenbe used with the boric with benefit. At

the higher temperatures, it is better to use the lower pH values. Nickel sulfamate can be used in concentrations up to saturation to replace the nickel sulfate, but it is not recommended in warm baths because of its hydrolysis;

Table II mso .1110 NiClaOHrO HIBO: Temp.,

;.' 1. g./l. 1.' '0 PH zoo-coo 35-45 35-40 40-00 2.5-4.5'

This application is a continuation-impart of my prior application Serial No. 396,854, filed June 6, 1941, which has become abandoned.

I claim:

1. The method of electrodepositing nickel which comprises electrolyning an aqueous acid solution comprising essentially a material selected from the group consisting of nickel chloride,

' I Number from 1.5 to 6 and the concentration of the sul- 6o fonated aryl sulfone falls within a range of from 1 gram per' liter to 5 grams per liter of solution. 3. A nickel plating bath comprising an aqueous selected from the group consisting of nickel chloride, nickel sulfate, a mixture of nickel chloride and nickel sulfate, a mixture of nickel sulfamate and nickel chloride, and a mixture of nickel chloride, nickel sulfate and nickel sulfamate. and mid solution having dissolved therein an organic compound selected from the group eonshtlng of sulfonlc acid derivatives of phenyl sulfones and sulfonic acid derivatives of naphthyl sulfones, said solution having a pH falling within a range d from 1.5 to 6. v

4. The bath as specified in claim 3 having a pH falling within a range of from 1.5 to 6 and wherein the sulionated aryl sulfcne has a concentrationfalling withinarangeoffmm lgram per liter to 5 grams per liter.

5. A bath for electrodepcsiting ductile bright nickel plate an aqueous add nickel solution comprising essentially amaterial selected from the group consisting of nickel sulfate, nickel chloride, a mixture of nickel sulfate and nickel chloride, a mixture of nickel sulfamate and nickel chloride, and a mixture of nickel chloride, nickel sulfate and nickel sulfamate, and said solution having dissolved therein dipheml sulfone s-sulfonic acid, said solution having a pH falling within a range of frome 1.5 to 6.

6. A bath for electrodepositlng ductile bright nickel plate comprising an aqueous acid nickel solution comprising essentially a material selected from the group consisting of nickel sulfate.

nlckdl chloride, 2. mixture of nickd sulfate and nickel chloride, a mixture of nickel culfamate and nickel chloride, and a mixture of nickel chloride, nickel sulfate and nickel sulfamate, and said solution having dissolved therein dlphenyl sulfone 3,3'-disulfonic acid, said solution having a pH falling within a range of from 1.5 to 6.'

may imown.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Stack Mar. 9, 1943 OTHER REFERENCES Metal Finishing, August 1940. Me 431. 

